Commutator-brush.



W h r EST A H N6. 736,048.

MLA Com PATENTED AUG. 11, 1903. c. WIRT.

COMMUTATOR BRUSH.

APPLICATION FILED JAN. 31. 1900- NO MODEL.

Witnesses lnvenlor Attorneys m: uc ms pnam re. hQILLITND. wnswNGYOm a c INO. 736,048.

concern/:- it known th'at I-I-Z CE'IARLES WIBT, a citiri "off the Unitedfitates, residing-at Phila- V delphia,iin the county of Philadelphia and State of'Pennsylvania, have invented a certain'inew anduseful Improvement; in Commutator-Brushes, description. v -j My invention relatesh to various uew and useful improvements in commutator-brushes; and the object of the inventionis to improve the etficiencyofi the brushes heretofore used.

of which the following is a j' Itfirhalv bacceptefas a general rule that the'best' performances-will be obtained with w a brnsh'lhaying thejhighest resistance consistentwith-tlre amount of. current to'be carried I As well- .kxiown, carbon is largely used for this purpose,'owin'g,to it's high resistance. In' most';cases,-'however,ithe resistance of the car bOII'jiS so highthat it becomes necessary to provideeither a large number of brushes or ailarge brush-surface and cross-section to do {the work;- By ms ns of 'my improved brush any desired high-resistance can be obtained and at the same time the brush will be more compact, have a smaller cross-section, and be cheaper than a carbon brush Of the same cait'will have a po ising or burnishing elfect. In on e comrnu a or w ere y the contact- .m and of the commuttatoriwill be kept always bright and clean. S'uch a'brush also will efiect a more uniform wear between the mica and the copper bars of the'commutator, owing to its polishing or burnishing action. I preferalso to make my improved commutator-brush of such achar- H actor that it will possess lubricating and smooth-running qualities. k

The several advantages to which I have referred and which my invention in its preferred formpossesses are preferably combinedin one and the same structure, or, in other' words, the commutator-brush is constructed so as to be of high resistance and to possess polishing or burnishing and lubricating or smooth-running qualities; but it will t be possible to construct a commutator-brush imposed,"some-or all of are coated on one or both sides wit a ver .thin coating 0 IHl 'l 188 pacity. I prefer to also make my improved" v mutator-brus o suc 7 which will bewithin the spirit of my present Patented August 11, 1903.

PATENT OFFICE.

CHARLES wrath, OEPHILAOELPHIA, PENNSYLVANIA, ASSIGNOR TO THE WIRT' ;E1:;EO;rRIc Oo PANY, INCORPORATEQA CORPORATION OF DELAWARE.

OMMuTAToR-BRusH.

'srncmchrrorirgmihg i ts of Letters Patent No. 736,048, dated August 11, 1903.

I Application filed- January 31, 1900. Serial No. 3,422. (No model.)

invention which may not possess allf'of such advantages and which will still be an e'ficient and valuable-article of manufacture. y

In carrying out my-invention .I prefer to construct the improved brush of a large number of very thin metal plates or gauzesu'perpoore ectrica con I 6o tor an w a aso, a ,lSOf sucha' sto pro see c esire o oerin-action D l i muons-mg or smooth-running qualities. The said thin superimposed plates are preferably rigidly secured together atone end by means of solder under pressure, and they are also: preferablygiven the desired rigidity by means of heavier clamping-plates extending on one or both sides of pleted brush. p

In order that my invention may be betterunderstood, attention is directed to the accompanying drawings, forming a part of this 7 specification, and in which 'Fignre 1 is aperspective vie'w of a commutator-brush embodying my present improve- -ments, and Fig. 2 a. longitudinal section of por-' tions of the said brush on a very much larger scale.

In both of the above views correspondipgi' 5 7 parts are represented by the same numerals of reference. V The brush'in its entirety is represented by the numeral 1. Said brush comprises, essentially, a large number of thin metal plates or gauze 2, which are superimposed and extend parallel, being shown as secured together at one end by solder 3, after the application of which the brush is subjected to pressure, so that its upper end will be slightly contracted to enable it to be more easily introduced into the brush-holder. The plates 2 2 are preferably composed of some good conducting material, such as copper or brass; but by reason oftheir extreme thinness they otter the desired longitudinal resistance to the current. This-longitudinal resistance may of course be increased by increasing the length of each of the plates or by decreasing their thickness. I find in practice that good results are obtained with a brush of the usual dimensions when the co'm jo" divied metals to ma e the eating slig y 2o conductive and at the same timeefiectte asst AValLABLEfigE n the said plates are each about .004 of an inch in thickness. Some or all of the plates 2 are coated on one or both sides with,a thin coating 4, which in practice and with the thick- 3 ness of plates mentioned may be about .003 of an inch in thickness. The coating 4 is of low electrical conductivity, and it also preferably is of such a character as will give to the completed brush the polishing or burnishr a ing eifect desired and also the lubricating or smooth-running qualities referred to. @ern f these properties are to be utilized, t e

coatin mav consls a S111 material ca a e 0 mm which w1lI harden with time or the appliation 0 ea s ,for examp 1 arul'sh or shellac, to which is added a small amount a "all: I a l lumll fi'nely- .ifflixugan: I 011160: 'shiug material, such as crocus or oter memy possess t e esiredstiffness, I prefer to em- .2 5 ploy two heavy plates 5 5 on either side thereof, and which are secured in place by the solder 3 during the manufacture of thebrush. As the brush wears away these plates may be filed ofi, so as not to come in contact with the o commutator. 7

By applying separate coatings of material of low electrical conductivity, as explained, to some or all of the plates the latter retain their individuality, so as to be properly fiexi 5 bl. In this respect my improved brush is distinguished from the composite brushes heretofore suggested,'which have been made either by folding or bending the plates upon each other or else by dipping the plates in a 4o coating material which serves to stickthem together. With the prior devices, therefore, the plates have not been capable of independent movement, so that the brushes have been lacking in flexibility.

5 By constructing the commutator-brush of very thin metal plates or gauze, between which are interposed coatings of poor conducting material, any desired transverse resistance may be obtained with all the advantages attendant on such construction and which will be appreciated by those skilled in .the art. By mixing with such a coating a lubricating material, such as graphite, the desired smoothu'unning qualities will be secured, while by adding to such coating a polishing material the commutator brush serves also as a burnisher of the commutator and in action will serve to keep the commutator and the contact-surface of the brush always smooth and clean.

It will be understood that instead of combining all the advantages explained in a single structure it will be possible to dispense with both the lubricating and polishing substances in the coating 4, in which case the brush will possess all the advantages of a carbon brush in its high longitudinal resis-- to obtaining low longitudinal conductivity,

but solely with regard to securing smoothrunning qualities, and it will, furthermore, be understood that it will be possible to employ between the conducting-plates a polishing or burnishing substance without regard either to obtaining low longitudinal conductivity or smooth-running qualities. It will be selfevident, however, that when the advantages enumerated are combined in a single article a more desirable commutator-brush in every way will be produced.

Having now described my invention, what I claim as new therein,and desire to secure by Letters Patent, is as follows: 1. An improved commutator-brush, comprising a plurality of thin, separate, superimposed plates, some or all of said plates be ing provided with a thin separate coating of poor electrical conducting material, substant-antially as set forth.

2. An improved commutator-brush, comprising a plurality of thin, separate, superimposed plates, some or all of saidplates being provided with a thin separate coating of poor electrical conducting material to which is added a polishing substance, substantially asset forth.

3. An improved commutator-brush, comprising a plurality of thin, separate, super-' imposed plates, some or all of said plates being provided with a thin separate coating of polishing material, substantially as set forth.

4. -An improved commutator-brush, comprising a plurality of thin, separate, superimposed plates, some or all of said plates being provided with a thin separate coating of lubricating material, substantially as set forth.

5. An improved commutator-brush, comprising a pluralityof thin, separate, superimposed plates, some or all of said plates being provided with a thin separate coatingof poor electrical conducting material to which is added a polishing substance and a lubrieating substance, substantially as set forth.

6. An improved commutator-brush, comprising a plurality of thin, separate, superimposed plates, some or all of said plates being provided with a thin separate coating of poor electrical conducting material, and stifiening plates on either side of the superimposed plates, substantially as set forth.

This specification signed and witnessed this 3d day of January, 1900.

CHARLES WIRT.

Witnesses:

ARCHIBALD G. REESE, J NO. R. TAYLOR. 

